/*
 * Copyright (C) 2013 Square, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package cn.nexd.app.okhttp.internal.http;

import java.io.IOException;
import java.net.ProtocolException;

import cn.nexd.app.okhttp.Protocol;
import cn.nexd.app.okhttp.Response;

/**
 * An HTTP response status line like "HTTP/1.1 200 OK".
 */
public final class StatusLine {
    /**
     * Numeric status code, 307: Temporary Redirect.
     */
    public static final int HTTP_TEMP_REDIRECT = 307;
    public static final int HTTP_PERM_REDIRECT = 308;
    public static final int HTTP_CONTINUE = 100;

    public final Protocol protocol;
    public final int code;
    public final String message;

    public StatusLine(Protocol protocol, int code, String message) {
        this.protocol = protocol;
        this.code = code;
        this.message = message;
    }

    public static StatusLine get(Response response) {
        return new StatusLine(response.protocol(), response.code(), response.message());
    }

    public static StatusLine parse(String statusLine) throws IOException {
        // H T T P / 1 . 1   2 0 0   T e m p o r a r y   R e d i r e c t
        // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0

        // Parse protocol like "HTTP/1.1" followed by a space.
        int codeStart;
        Protocol protocol;
        if (statusLine.startsWith("HTTP/1.")) {
            if (statusLine.length() < 9 || statusLine.charAt(8) != ' ') {
                throw new ProtocolException("Unexpected status line: " + statusLine);
            }
            int httpMinorVersion = statusLine.charAt(7) - '0';
            codeStart = 9;
            if (httpMinorVersion == 0) {
                protocol = Protocol.HTTP_1_0;
            } else if (httpMinorVersion == 1) {
                protocol = Protocol.HTTP_1_1;
            } else {
                throw new ProtocolException("Unexpected status line: " + statusLine);
            }
        } else if (statusLine.startsWith("ICY ")) {
            // Shoutcast uses ICY instead of "HTTP/1.0".
            protocol = Protocol.HTTP_1_0;
            codeStart = 4;
        } else {
            throw new ProtocolException("Unexpected status line: " + statusLine);
        }

        // Parse response code like "200". Always 3 digits.
        if (statusLine.length() < codeStart + 3) {
            throw new ProtocolException("Unexpected status line: " + statusLine);
        }
        int code;
        try {
            code = Integer.parseInt(statusLine.substring(codeStart, codeStart + 3));
        } catch (NumberFormatException e) {
            throw new ProtocolException("Unexpected status line: " + statusLine);
        }

        // Parse an optional response message like "OK" or "Not Modified". If it
        // exists, it is separated from the response code by a space.
        String message = "";
        if (statusLine.length() > codeStart + 3) {
            if (statusLine.charAt(codeStart + 3) != ' ') {
                throw new ProtocolException("Unexpected status line: " + statusLine);
            }
            message = statusLine.substring(codeStart + 4);
        }

        return new StatusLine(protocol, code, message);
    }

    @Override
    public String toString() {
        StringBuilder result = new StringBuilder();
        result.append(protocol == Protocol.HTTP_1_0 ? "HTTP/1.0" : "HTTP/1.1");
        result.append(' ').append(code);
        if (message != null) {
            result.append(' ').append(message);
        }
        return result.toString();
    }
}
